Display apparatus and method of manufacturing the same

ABSTRACT

A display apparatus and a method of manufacturing the display method are provided. The display apparatus includes a transfer substrate, and micro display elements spaced apart from each other in units of sub-pixels on the transfer substrate, wherein each of the micro display elements includes a micro light emitting unit and a drive unit, wherein the drive unit includes drive electrodes and drives the micro light emitting unit.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.17/506,359, filed Oct. 20, 2021, which application is based on andclaims priority under 35 U.S.C. § 119 to U.S. Provisional ApplicationNo. 63/125,621, filed on Dec. 15, 2020, in the United States Patent andTrademark Office, and Korean Patent Application No. 10-2021-0054629,filed on Apr. 27, 2021, in the Korean Intellectual Property Office, thedisclosures of which are incorporated by reference herein in theirentireties.

BACKGROUND 1. Field

Example embodiments relate to a micro light emitting element withincreased luminous efficiency and a display apparatus including themicro light emitting element.

2. Description of Related Art

Liquid crystal displays (LCDs) and organic light emitting diode (OLED)displays are widely used as display apparatuses. Recently, a technologyfor manufacturing a high-resolution display apparatus by using a microlight emitting diode (LED) has been in the spotlight. In manufacturing adisplay apparatus including micro LED chips, a pick and place method isused as a method of transferring micro LEDs. However, when using thismethod, productivity is reduced as a size of a micro LED is reduced anda size of a display is increased.

A related art display apparatus includes a backplane substrate on whichthin film transistors (TFTs) are integrated and to which organic lightemitting diodes (OLEDs) and liquid crystal displays (LCDs) serving aslight emitting elements are coupled. However, types of the TFTs that maybe deposited are limited depending on the type and size of the backplanesubstrate, and thus, designs of the TFTs may be changed. Respectivemicro LEDs are transferred onto a TFT-formed substrate, and thus, themicro LEDs have the same limitation.

SUMMARY

One or more example embodiments provide a display apparatus including amicro display element.

One or more example embodiments also provide a method of manufacturing adisplay apparatus having a large area.

Additional aspects will be set forth in part in the description whichfollows and, in part, will be apparent from the description, or may belearned by practice of embodiments of the disclosure.

In accordance with an aspect of an example embodiment, a displayapparatus including a transfer substrate; and micro display elementsspaced apart from each other in units of sub-pixels on the transfersubstrate, wherein each of the micro display elements includes a microlight emitting unit and a drive unit, wherein the drive unit includesdrive electrodes and drives the micro light emitting unit, and whereinthe drive unit faces the micro light emitting unit.

The drive unit may be monolithically coupled to the micro light emittingunit.

The drive unit and the micro light emitting unit may have a same width.

Each of the micro display elements may further include an insulatinglayer between the micro light emitting unit and the drive unit anddivided in the units of the sub-pixels.

Each drive electrode from among the drive electrodes may be provided ata different distance from a center of the drive unit.

The drive unit may include a first quadrant, a second quadrant, a thirdquadrant, and a fourth quadrant that are partitioned by a first axispassing through a center of the drive unit and a second axis passingthrough the center of the drive unit perpendicular to the first axis,and the drive electrodes may be respectively provided in the firstquadrant, the second quadrant, the third quadrant, and the fourthquadrant.

Each of the drive electrodes may be provided at a different distancefrom the center of the drive unit.

The drive electrodes may be symmetrically arranged with respect to afirst axis passing through a center of the drive unit and a second axispassing through the center of the drive unit perpendicular to the firstaxis.

Each of the drive electrodes may include any one from among a concentriccircle structure, a concentric quadrangular structure, a concentrichexagonal structure, a four-divided concentric circle structure, afour-divided concentric quadrangular structure, a four-dividedconcentric hexagonal structure, and a six-divided concentric hexagonalstructure.

The drive unit may include two or more transistors and one or morecapacitors.

The micro light emitting unit may include electrodes, and the microlight emitting unit may have a horizontal electrode structure in whichthe electrodes are arranged in one direction.

Each of the micro display elements may have an asymmetric structure, andthe drive electrodes included in each of the micro display elements maybe arranged side by side.

Each of the micro display elements may further include a reflectivelayer between the micro light emitting unit and the drive unit.

In accordance with an aspect of an example embodiment, a method ofmanufacturing a display apparatus includes forming a micro lightemitting unit on a growth substrate; forming a drive unit over the microlight emitting unit, the drive unit including drive electrodes and beingconfigured to drive the micro light emitting unit; removing the growthsubstrate; forming micro display elements by dividing the micro lightemitting unit and the drive unit together in units of sub-pixels; andtransferring the micro display elements onto a transfer substrate to beapart from each other.

The drive unit may be monolithically coupled to the micro light emittingunit.

The drive unit and the micro light emitting unit may have a same width.

The method may further include forming an insulating layer between themicro light emitting unit and the drive unit; and dividing the microlight emitting unit, the drive unit, and the insulating layer togetherin the units of the sub-pixels.

Each of the drive electrodes may be provided at a different distancefrom a center of the drive unit.

The drive unit may include a first quadrant, a second quadrant, a thirdquadrant, and a fourth quadrant that are partitioned by a first axispassing through a center of the drive unit and a second axis passingthrough the center of the drive unit perpendicular to the first axis,and the drive electrodes may be respectively provided in the firstquadrant, the second quadrant, the third quadrant, and the fourthquadrant.

Each of the drive electrodes may be provided at a different distancefrom the center of the drive unit.

The drive electrodes may be symmetrically arranged with respect to afirst axis passing through a center of the drive unit and a second axispassing through the center of the drive unit perpendicular to the firstaxis.

Each of the drive electrodes may include any one from among a concentriccircle structure, a concentric quadrangular structure, a concentrichexagonal structure, a four-divided concentric circle structure, afour-divided concentric quadrangular structure, a four-dividedconcentric hexagonal structure, and a six-divided concentric hexagonalstructure.

The drive unit may include two or more transistors and one or morecapacitors.

The micro light emitting unit may include electrodes, and the microlight emitting unit may have a horizontal electrode structure in whichthe electrodes are arranged in one direction.

Each of the micro display elements may have an asymmetric structure, andthe drive electrodes included in each of the micro display elements maybe arranged side by side.

The display apparatus may further include a reflective layer between themicro light emitting unit and the drive unit.

The micro display elements may be transferred onto the transfersubstrate by a fluidic self-assembly method.

In accordance with an aspect of the disclosure, a micro display elementincludes a micro light emitting unit; and a thin film transistor (TFT)drive unit monolithically formed on the micro light emitting unit.

The TFT drive unit may include drive electrodes on a side of the TFTdrive unit facing away from the micro light emitting unit.

The drive electrodes may be concentrically arranged on the side of theTFT drive unit with at least one from among linear symmetry, pointsymmetry, and rotational symmetry.

The drive electrodes may be asymmetrically arranged on the side of theTFT.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features, and advantages of certainembodiments of the disclosure will be more apparent from the followingdescription taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 is a schematic cross-sectional view of a display apparatusaccording to an example embodiment;

FIG. 2 illustrates a micro display element of a display apparatusaccording to an example embodiment;

FIGS. 3 to 8 are views illustrating examples of drive electrodesincluded in a drive unit of a display apparatus according to an exampleembodiment;

FIG. 9 illustrates a comparative example of a transfer method of adisplay apparatus;

FIG. 10 illustrates a transfer method of a display apparatus accordingto an example embodiment;

FIG. 11 illustrates an example of a micro display element of a displayapparatus according to an example embodiment;

FIG. 12 illustrates a display apparatus according to an exampleembodiment;

FIG. 13 illustrates an example in which a color conversion layer isfurther provided in the display apparatus illustrated in FIG. 1 ;

FIG. 14 is a flowchart illustrating a method of manufacturing a displayapparatus according to an example embodiment;

FIG. 15 illustrates a micro light emitting unit and a drive unit formedon a growth substrate by using a method of manufacturing a displayapparatus according to an example embodiment;

FIG. 16 illustrates micro display elements formed by removing the growthsubstrate from the structure illustrated in FIG. 15 ;

FIG. 17 illustrates transferring a micro display element onto a transfersubstrate in a method of manufacturing a display apparatus according toan example embodiment;

FIG. 18 is a schematic block diagram of an electronic apparatusaccording to an example embodiment;

FIG. 19 illustrates an example in which a display apparatus according toan example embodiment is applied to a mobile apparatus;

FIG. 20 illustrates an example in which a display apparatus according toan example embodiment is applied to a vehicle display apparatus;

FIG. 21 illustrates an example in which a display apparatus according toan example embodiment is applied to augmented reality glasses;

FIG. 22 illustrates an example in which a display apparatus according toan example embodiment is applied to a signage; and

FIG. 23 illustrates an example in which a display apparatus according toan example embodiment is applied to a wearable display.

DETAILED DESCRIPTION

Reference will now be made in detail to embodiments, examples of whichare illustrated in the accompanying drawings, wherein like referencenumerals refer to like elements throughout. In this regard, embodimentsmay have different forms and should not be construed as being limited tothe descriptions set forth herein. Accordingly, embodiments are merelydescribed below, by referring to the figures, to explain aspects. Asused herein, the term “and/or” includes any and all combinations of oneor more of the associated listed items. Expressions such as “at leastone of,” when preceding a list of elements, modify the entire list ofelements and do not modify the individual elements of the list.

Hereinafter, a display apparatus and a method of manufacturing thedisplay apparatus according to various embodiments will be described indetail with reference to the accompanying drawings. In the drawings,like reference numerals refer to like elements, and a size of eachelement in the drawings may be exaggerated for clarity and convenienceof description. The terms “first”, “second”, and so on may be used todescribe various configuration elements but configuration elementsshould not be limited by terms. Terms are only used for the purpose ofdistinguishing one configuration element from another configurationelement.

A singular expression includes plural expressions unless the contextclearly indicates otherwise. In addition, when a part is described to“include” a certain configuration element, which means that the part mayfurther include other configuration elements, except to exclude otherconfiguration elements unless otherwise stated. In addition, in thedrawings, a size or a thickness of each configuration element may beexaggerated for the sake of clear description. In addition, when it isdescribed that a certain material layer is formed on a substrate oranother layer, the material layer may also be formed in direct contactwith the substrate or another layer, or a third layer may be formedtherebetween. In addition, in the following examples, materials formingrespective layers are examples, and other materials may be used.

In addition, terms such as “unit”, “portion”, and “module” described inthe specification may indicate units that process at least one functionor operation, which may be configured by hardware, software, or acombination of hardware and software.

Specific implementations described in the disclosure are examples and donot limit the technical scope in any way. For the sake of briefspecification, descriptions of electronic configurations of the relatedart, control systems, software, and other functional aspects of thesystems may be omitted. In addition, connection or connection members oflines between configuration elements illustrated in the drawingsexemplarily represent functional connections and/or physical or circuitconnections, and may be represented as alternative or additional variousfunctional connections, physical connections, or circuit connections inan actual apparatus.

Use of a term “above-described” and a similar reference term maycorrespond to both the singular and the plural.

Steps constituting a method are not limited in the order described andmay be performed in any suitable order unless there is a clear statementthat the steps should be performed in the order described. In addition,use of all example terms (“for example” and “and so on”) is merely fordescribing technical ideas in detail, and the scope of the claims arenot limited to the terms unless limited by claims.

FIG. 1 illustrates a display apparatus according to an exampleembodiment.

A display apparatus 100 includes a plurality of pixels, and only onepixel is illustrated in FIG. 1 for the sake of convenience. The pixelmay be a unit for displaying an image. Each of the pixels may includesub-pixels that emit light of different colors. An image may bedisplayed by the different colors from the sub-pixels by controlling theamount of light emitted by each sub-pixel. For example, each pixel mayinclude a first sub-pixel SP1, a second sub-pixel SP2, and a thirdsub-pixel SP3.

The display apparatus 100 includes a transfer substrate 110 and microdisplay elements 120 arranged to be apart from each other in units ofsub-pixels on the transfer substrate 110. The micro display elements 120are transferred onto the transfer substrate 110, and the transfersubstrate 110 may include a single layer or a plurality of layers. Thetransfer substrate 110 may have a single body or a single mold structureincluding a plurality of grooves 105. The transfer substrate 110 mayinclude, for example, an organic material such as silicon, glass,sapphire, or polymer, an inorganic material, and/or a metal, and may bemanufactured by photoresist patterning, etching, molding, and so on, butembodiments are not limited thereto. The grooves 105 may guide the microdisplay elements 120 when the micro display elements 120 are transferredonto the transfer substrate 110.

The grooves 105 may have cross-sectional areas that are wider than areasof the micro display elements 120 to accommodate the micro displayelements 120. The grooves 105 may each have an area in which only onemicro display element 120 may be placed or a plurality of micro displayelements 120 may be placed. The grooves 105 may each have a shapesimilar to a cross-section of each of the micro display elements 120,for example, a circular cross-section or a polygonal cross-section. Thegrooves 105 may each have a depth d that is less than or greater than athickness of each of the micro display elements 120, for example, adepth d less than twice the thickness of each of the micro displayelements 120, or a depth d in a range of 0.5 to 1.5 times the thicknessof each of the micro display elements 120. In addition, a bottom surfaceof each of the grooves 105 may have a roughness of about 50 nm or less.

A metal layer 103 may be further provided on a surface of the transfersubstrate 110. The metal layer 103 may include Ag, Au, Pt, Ni, Cr,and/or Al, and may have a surface energy that is different from asurface energy of the transfer substrate 110. A polymer may be furthercoupled to the metal layer 103. A difference in surface energy not onlyenables the micro display element 120 to be transferred into the groove105 well, but also enables the micro display element 120 that is nottransferred into the groove 105 and remains on the surface of thetransfer substrate 110 to be separated well from the transfer substrate110 in a cleaning step. The metal layer 103 may be selected from amonghydrophobic materials, and the groove 105 may be selected from amonghydrophilic materials such that the metal layer 103 has a largedifference in surface energy.

FIG. 2 illustrates one of the micro display elements 120.

The micro display element 120 may include a micro light emitting unit130 and a drive unit 140 that drives the micro light emitting unit 130.For example, the micro display element 120 may have a width (w) of 200μm or less. The micro display element 120 may be used as a transferelement.

The drive unit 140 may be arranged to face the micro light emitting unit130. The drive unit 140 may have a structure monolithically coupled tothe micro light emitting unit 130. The monolithically coupled structuremay be a structure in which the drive unit 140 is integrally coupled tothe micro light emitting unit 130 without an adhesive layer. The microdisplay element 120 may be cut in units of sub-pixels in a state wherethe micro light emitting unit 130 is integrated with the drive unit 140,and the drive unit 140 may have the same width was the micro lightemitting unit 130.

An insulating layer 139 may be between the micro light emitting unit 130and the drive unit 140. The insulating layer 139 may be divided in unitsof sub-pixels together with the micro light emitting unit 130 and thedrive unit 140. Accordingly, the insulating layer 139 may have the samewidth w as the micro light emitting unit 130 and the drive unit 140.

The drive unit 140 may include drive electrodes 150 for driving themicro light emitting unit 130. The drive electrodes 150 may supplycurrent to the micro light emitting unit 130 and may be provided atpositions corresponding to the micro light emitting unit 130. That is,the drive electrodes 150 may be provided in regions of the drive unit140 corresponding to the micro light emitting unit 130 on a surface ofthe drive unit 140 facing away from the micro light emitting unit 130.The drive electrodes 150 may constitute a transistor, a capacitor, or soon. A layer including the drive unit 140 may include one of lowtemperature poly silicon, low temperature poly oxide, amorphous silicon(a-Si), and oxide.

The micro light emitting unit 130 may include a first semiconductorlayer 131, a light emitting layer 132, and a second semiconductor layer133 that are sequentially stacked. The first semiconductor layer 131 mayinclude a first type semiconductor. For example, the first semiconductorlayer 131 may include an n-type semiconductor. The first semiconductorlayer 131 may include a group III-V-based n-type semiconductor, forexample, n-GaN. The first semiconductor layer 131 may have asingle-layer structure or a multi-layer structure.

The light emitting layer 132 may be provided on an upper surface of thefirst semiconductor layer 131. Electrons and holes in the light emittinglayer 132 combine to emit light. The light emitting layer 132 may have amulti-quantum well (MQW) structure or a single quantum well (SQW)structure. The light emitting layer 132 may include a group III-V-basedsemiconductor, for example, GaN.

The second semiconductor layer 133 may be provided on an upper surfaceof the light emitting layer 132. The second semiconductor layer 133 mayinclude, for example, a p-type semiconductor. The second semiconductorlayer 133 may include a group III-V-based p-type semiconductor, forexample, p-GaN. The second semiconductor layer 133 may have asingle-layer structure or a multi-layer structure. Alternatively, whenthe first semiconductor layer 131 includes a p-type semiconductor, thesecond semiconductor layer 133 may include an n-type semiconductor.

A first electrode 135 electrically connected to the first semiconductorlayer 131 may be provided, and a second electrode 136 electricallyconnected to the second semiconductor layer 133 may be provided. Thefirst electrode 135 may include a pixel electrode, and the secondelectrode 136 may include a common electrode. When the firstsemiconductor layer 131 and the second semiconductor layer 133respectively include an n-type semiconductor and a p-type semiconductor,the first electrode 135 and the second electrode 136 may respectivelyinclude an n-type electrode and a p-type electrode. The first electrode135 may be connected to the first semiconductor layer 131 through avia-metal 137. The micro light emitting unit 130 may have a horizontalelectrode structure in which electrodes are arranged in one direction.

The drive unit 140 may be electrically connected to the first electrode135 and the second electrode 136, and the drive unit 140 may controlon-off of power. Therefore, the drive unit 140 may selectively drive atleast one desired sub-pixel among the first sub-pixel SP1, the secondsub-pixel SP2, and the third sub-pixel SP3.

The first electrode 135 and the second electrode 136 may each include areflective material to reflect light emitted from the light emittinglayer 132. The first electrode 135 and the second electrode 136 may eachinclude, for example, Ag, Au, Al, Cr or Ni, or an alloy thereof.Alternatively, the first electrode 135 and the second electrode 136 maybe formed as transparent electrodes to transmit light emitted from thelight emitting layer 132. The transparent electrode may include, forexample, indium tin oxide (ITO), zinc oxide (ZnO), indium zinc oxide(IZO), or indium gallium zinc oxygen (IGZO).

The drive unit 140 may include a transistor, a thin film transistor, ora high electron mobility transistor (HEMT) for electrically driving themicro light emitting unit 130. The drive electrodes 150 may include, forexample, a source electrode, a drain electrode, or a gate electrodeconstituting the transistor. Alternatively, the drive unit 140 mayinclude a capacitor. The drive electrodes 150 may constitute acapacitor. The drive unit 140 may include, for example, two or moretransistors and one or more capacitors but is not limited thereto. Thetwo transistors may include a drive transistor for supplying a currentto the micro light emitting unit 130 and a switching transistorfunctioning as a switch.

The drive electrodes 150 may be connected to the first electrode 135 andthe second electrode 136 of the micro light emitting unit 130.

FIG. 3 is a plan view of drive electrodes 150 of the drive unit 140. Thedrive electrodes 150 may be provided at different radial positions ordifferent distances from the center c of the drive unit 140. The driveelectrodes 150 may include a first drive electrode 151 provided at thecenter c of the drive unit 140, and may further include a second driveelectrode 152, a third drive electrode 153, and a fourth drive electrode154 of a closed-loop type provided around the first drive electrode 151.Here, the drive electrodes 150 may include only the second driveelectrode 152, the third drive electrode 153, and the fourth driveelectrode 154 of the closed-loop type without the first drive electrode151. As illustrated in FIG. 3 , the drive electrodes 150 may have asymmetrical structure. For example, the drive electrodes 150 may have alinearly symmetrical structure, a point symmetrical structure, or arotationally symmetrical structure but are not limited thereto.

FIG. 3 illustrates an example in which the drive electrodes 150 have aconcentric circle structure. The drive electrodes 150 may include afirst drive electrode 151 provided at the center c of the drive unit140, and may further include a second drive electrode 152, a third driveelectrode 153, and a fourth drive electrode 154 of a closed-loop typeprovided around the first drive electrode 151. In a case where the driveelectrodes 150 are configured in this way, when the micro displayelement 120 is transferred onto the transfer substrate 110, electrodepads may be connected to the drive electrodes 150 regardless of atransfer direction of the micro display element 120. For example, whenthe drive electrodes 150 include the first drive electrode 151, thesecond drive electrode 152, the third drive electrode 153, and thefourth drive electrode 154 and a first electrode pad P1, a secondelectrode pad P2, a third electrode pad P3, and a fourth electrode padP4 are provided, the first drive electrode 151 may be connected to thefirst electrode pad P1, the second drive electrode 152 may be connectedto the second electrode pad P2, the third drive electrode 153 may beconnected to the third electrode pad P3, and the fourth drive electrode154 may be connected to the fourth electrode pad P4. When the driveelectrodes 150 have a concentric circle structure, no matter whichdirection the micro display element 120 is transferred onto the transfersubstrate 110, the first drive electrode 151, the second drive electrode152, the third drive electrode 153, and the fourth drive electrode 154may be respectively connected to the first, second, third, and fourthelectrode pads P1, P2, P3, and P4 corresponding thereto. As such, thedrive electrodes 150 may be connected to corresponding electrode padsregardless of a transfer direction of the micro display element 120.

FIG. 4 illustrates an example of the drive electrodes of the drive unit.The drive electrodes 150 may have a concentric quadrangular structure.The concentric quadrangular structure may include a quadrangular firstdrive electrode 151 provided at the center c of the drive unit 140, andmay further include the second drive electrode 152, the third driveelectrode 153, and the fourth drive electrode 154 each having a shape ofa quadrangular ring provided around the first drive electrode 151.

FIG. 5 illustrates an example of the drive electrodes of the drive unit.The drive electrodes 150 may have a concentric hexagonal structure. Theconcentric hexagonal structure may include a hexagonal first driveelectrode 151 provided at the center c of the drive unit 140, and mayfurther include the second drive electrode 152, the third driveelectrode 153, and the fourth drive electrode 154 each having a shape ofa hexagonal ring provided around the first drive electrode 151.

FIG. 6 illustrates an example of the drive electrodes of the drive unit.The drive electrodes 150 may have a four-divided concentric quadrangularstructure. Here, the four divisions are not limited to an equaldivision. The drive unit 140 may include a first quadrant A1, a secondquadrant A2, a third quadrant A3, and a fourth quadrant A4 partitionedby a first axis X and a second axis Y perpendicularly passing throughthe center c. The first drive electrode 151, the second drive electrode152, the third drive electrode 153, and the fourth drive electrode 154may be respectively provided in all of the first quadrant A1, the secondquadrant A2, the third quadrant A3, and the fourth quadrant A4. Each ofthe quadrants may include a pair of the second drive electrode 152, thethird drive electrode 153, and the fourth drive electrode 154 or twopairs of the second drive electrode 152, the third drive electrode 153,and the fourth drive electrode 154. The drive electrodes 150 may besymmetrically arranged with respect to the first axis X and the secondaxis Y.

FIG. 7 illustrates an example of the drive electrodes of the drive unit.The drive electrodes 150 may have a four-divided concentric hexagonalstructure. Here, the four divisions are not limited to an equaldivision. FIG. 7 illustrates an example in which the concentrichexagonal structure is divided into four portions but may be dividedinto six portions. The drive unit 140 may include a first quadrant A1, asecond quadrant A2, a third quadrant A3, and a fourth quadrant A4partitioned by a first axis X and a second axis Y perpendicularlypassing through a center c. Each of the drive electrodes 150 may beprovided in each of the first quadrant A1, the second quadrant A2, thethird quadrant A3, and the fourth quadrant A4. Each of the quadrants mayinclude a pair of the drive electrodes 150 or two pairs of the driveelectrodes 150. The drive electrodes 150 may be symmetrically arrangedwith respect to the first axis X and the second axis Y. The driveelectrodes 150 may include the first drive electrode 151, the seconddrive electrode 152, the third drive electrode 153, and the fourth driveelectrode 154, and the first drive electrode 151, the second driveelectrode 152, the third drive electrode 153, and the fourth driveelectrode 154 need not have the same shape.

FIG. 8 illustrates an example of the drive electrodes of the drive unit.In an embodiment, a micro display element 220 may have an asymmetricstructure, and drive electrodes 250 may be arranged side by side. Atransfer substrate 210 may include a plurality of grooves 205, and theplurality of grooves 205 may have an asymmetric structure. A shape ofthe groove 205 may correspond to a shape of the micro display element220. For example, the micro display element 220 and the groove 205 mayhave a trapezoidal shape. The groove 205 may have a first side 205 a anda second side 205 b that face each other, and the micro display element220 may have a third side 220 a and a fourth side 220 b that face eachother. A length d4 of the fourth side 220 b may be greater than a lengthdl of the first side 205 a such that the micro display element 220 maybe transferred into the groove 205 with a certain directionality.Therefore, the micro display element 220 may be transferred tocorrespond to the shape of the groove 205. In addition, the driveelectrodes 250 may be arranged with directionality. For example, whenthe drive electrodes 250 include a first drive electrode 251, a seconddrive electrode 252, a third drive electrode 253, a fourth driveelectrode 254, a fifth drive electrode 255, and a sixth drive electrode256, the first drive electrode 251, the second drive electrode 252, thethird drive electrode 253, the fourth drive electrode 254, the fifthdrive electrode 255, and the sixth drive electrode 256 may be arrangedside by side at different distances from any one point m of the driveunit. When the drive electrodes are arranged in this way, the firstdrive electrode 251, the second drive electrode 252, the third driveelectrode 253, the fourth drive electrode 254, the fifth drive electrode255, and the sixth drive electrode 256 may be respectively connected toelectrode pads corresponding thereto. According to an embodiment, whenit is difficult to secure an area because the required number ofelectrodes is large compared to a size of a micro display element, anarea of the electrode may be reduced and an error rate of connection toan electrode pad may be reduced.

The display apparatuses according to various embodiments described abovemay be manufactured by transferring micro display elements to transfersubstrates. FIG. 9 illustrates a comparative example in which lightemitting units L are formed on a wafer WP and are separated from thewafer WP to be transferred onto a transfer substrate TB. In thecomparative example, drive units DD for driving the light emitting unitsL are formed on the transfer substrate TB. The separated light emittingunits L may be transferred onto the transfer substrate TB to be coupledto the drive units DD. As such, when the drive units DD are provided inthe transfer substrate TB, there are restrictions on a type and amaterial of the transfer substrate TB.

FIG. 10 is a view illustrating an example in which a micro displayelement is transferred onto a transfer substrate according to an exampleembodiment. A micro display element 320 includes both of a micro lightemitting unit 330 grown on a wafer (growth substrate) 305 and a driveunit 340 monolithically integrated in the micro light emitting unit 330.The micro display element 320 is divided in units of individual chipsand transferred onto the transfer substrate 310. Wiring lines 315 may beformed on the transfer substrate 310. Only wiring lines are formed onthe transfer substrate 310, and thus, there may be no restriction on atype and a material of the transfer substrate 310.

As illustrated in FIG. 9 , when the micro light emitting unit formed ona wafer is moved onto the transfer substrate TB on which thin filmtransistors (TFTs) are formed, types of the TFTs may be limited by thetransfer substrate TB. In contrast to this, as illustrated in FIG. 10 ,when a micro display element in which the drive unit 340 including theTFT is monolithically integrated in the micro light emitting unit 330 tobe diced is transferred onto the transfer substrate 310, substrateselection for forming the TFT is no longer limited, and thus, displaysmay be formed on various substrates. When TFTs are formed by a lowtemperature poly-silicon (LTPS) process on a general wafer where microlight emitting diodes (LEDs) are formed, many restrictions on TFTselection may be reduced. A micro display element in which a micro LEDand a TFT are combined may be effectively transferred onto a large-areasubstrate by using a fluidic self-assembly method.

FIG. 11 illustrates an example in which a reflective layer is furtherprovided in the micro display element illustrated in FIG. 2 . Componentsof FIG. 11 having the same reference numerals as the components of FIG.2 have substantially the same functions and configurations as describedwith reference to FIG. 2 , and thus, detailed descriptions thereof areomitted.

A micro display element 120A may further include a reflective layer 160between the micro light emitting unit 130 and the drive unit 140. Thereflective layer 160 may be, for example, a distributed Bragg reflectivelayer. The reflective layer 160 may include a first layer 161 and asecond layer 162, which have different refractive indices and arealternately stacked a plurality of times. Due to a difference inrefractive index, all waves reflected from interfaces of respectivelayers may interfere with each other. The distributed Bragg reflectivelayer 160 may have a structure in which layers including two of, forexample, Si, Si₃N₄, SiO₂, TiO₂, Ta₂O₅, and ZrO₂ are alternately stacked.The distributed Bragg reflective layer 160 may have a structure inwhich, for example, an SiO₂ layer and a TiO₂ layer are alternatelystacked. Light reflectivity may be adjusted by thicknesses of two layersof the reflective layer 160 and the number of stacks thereof. Thereflective layer 160 may reflect light emitted from the micro lightemitting unit 130 to be emitted in a downward direction as shown in FIG.11 .

FIG. 12 illustrates a display apparatus according to an exampleembodiment. The display apparatus 300 may include the transfer substrate310 and the micro display element 120 provided to be apart from thetransfer substrate 310. The micro display element 120 is substantiallythe same as the micro display element described with reference to FIG. 2, and thus, detailed descriptions thereof are omitted. The transfersubstrate 310 may be a flat substrate and may be arranged such that thedrive unit 140 faces the transfer substrate 310. The micro displayelement 120 may be bonded to the transfer substrate 310.

FIG. 13 illustrates an example in which a color conversion layer isfurther provided in the display apparatus described with reference toFIGS. 1 and 2 . Components of FIG. 13 having the same reference numbersas the components of FIGS. 1 and 2 have substantially the same functionsand configurations as described with reference to FIGS. 1 and 2 , andthus, detailed descriptions thereof are omitted.

A display apparatus 300A may include partition walls 371 separated fromeach other at sub-pixel intervals, and color conversion layers 380provided between adjacent partition walls 371. The color conversionlayers 380 may each convert a color of light emitted from the microlight emitting unit 130. The micro light emitting unit 130 may emitfirst color light, for example, blue light. However, this is only anexample, and light having another wavelength capable of exciting thecolor conversion layers may also be emitted. A planarization layer 360may be further provided between the drive unit 140 and the colorconversion layers 380.

The color conversion layers 380 include a first color conversion layer381 that converts light from the micro light emitting unit 130 intofirst color light, a second color conversion layer 382 that converts thelight into second color light, and a third color conversion layer 383that convers light into third color light. The second color light maybe, for example, green light, and the third color light may be, forexample, red light.

When the micro light emitting unit 130 emits blue light, the first colorconversion layer 381 may include a resin that transmits blue lightwithout light conversion. The second color conversion layer 382 mayconvert blue light emitted from the micro light emitting unit 130 toemit green light. The second color conversion layer 382 may includequantum dots that are excited by blue light to emit green light, andeach of the quantum dots may have a core-shell structure including acore portion and a shell portion or may have a particle structurewithout a shell. The core-shell structure may be a single-shellstructure or a multi-shell structure, such as a double-shell structure.

Each of the quantum dots may include a group II-VI-based semiconductor,a group III-V-based semiconductor, a group IV-VI-based semiconductor, agroup IV-based semiconductor, and/or a graphene quantum dot. The quantumdots may include, for example, Cd, Se, Zn, S, and/or InP, and each ofthe quantum dots may have a diameter of several tens of nm or less, forexample, a diameter of about 10 nm or less.

The second color conversion layer 382 may also include a phosphor thatis excited by blue light emitted from the micro light emitting unit 130to emit green light.

The third color conversion layer 383 may convert the blue light emittedfrom the micro light emitting unit 130 into red light and emit the redlight. The third color conversion layer 383 may include quantum dots ofa certain size that are excited by blue light to emit red light or mayinclude a phosphor that is excited by the blue light emitted from themicro light emitting unit 130 to emit red light.

FIG. 14 is a flowchart illustrating a method of manufacturing a displayapparatus according to an example embodiment.

Referring to FIGS. 14 and 15 , the method of manufacturing a displayapparatus includes a step of forming a micro light emitting unit 430 ona growth substrate 405 (S10), and a step of forming a drive unit 440,which includes drive electrodes 450 and drives the micro light emittingunit 430, on the micro light emitting unit 430 (S20). The micro lightemitting unit 430 includes a first semiconductor layer 431 formed on thegrowth substrate 405, a light emitting layer 432 formed on the firstsemiconductor layer 431, and a second semiconductor layer 433 formed onthe light emitting layer 432. The first semiconductor layer 431, thelight emitting layer 432, and the second semiconductor layer 433 may beintegrally formed over the entire pixel region without being dividedinto units of sub-pixels. The drive unit 440 may be monolithicallyformed on the second semiconductor layer 433. The drive electrodes 450of the drive unit 440 may each have the same structure as described withreference to FIGS. 3 to 8 . An insulating layer 439 may be formedbetween the second semiconductor layer 433 and the drive unit 440.

Referring to FIGS. 14 and 16 , the growth substrate 405 is removed fromthe first semiconductor layer 431 (S30), and the micro light emittingunit 430 and the drive unit 440 are divided together in units ofsub-pixels to form the micro display elements 420 (S40). In a state inwhich the micro light emitting unit 430 is integrated with the driveunit 440, the micro light emitting unit 430 and the drive unit 440 areseparated by cutting in units of sub-pixels or by using an etchingprocess, and thus, a micro display element 420 is formed.

Referring to FIGS. 14 and 17 , micro display elements 520 aretransferred onto a transfer substrate 510 (S50). The transfer substrate510 includes a plurality of grooves 505 in which the micro displayelements 520 are arranged. A liquid may be supplied to the grooves 505to transfer the micro display elements 520 to the grooves 505. Any kindof liquid may be used as long as the liquid does not corrode or damagethe micro display elements 520. The liquid may include, for example, oneor a combination of a plurality of groups, each group including, forexample, water, ethanol, alcohol, polyol, ketone, halocarbon, acetone,flux, and organic solvent. The organic solvent may include, for example,isopropyl alcohol (IPA). A usable liquid is not limited thereto, andvarious modifications may be made.

A method of supplying a liquid to the grooves 505 may include variousmethods such as a spray method, a dispensing method, an inkjet dotmethod, and a method of flowing the liquid to the transfer substrate510. The amount of liquid that is supplied to the grooves 505 may beadjusted to fit or overflow the grooves 505.

A plurality of micro display elements 520 may be supplied to thetransfer substrate 510. The micro display elements 520 may be directlysprayed onto the transfer substrate 510 without other liquids or may besupplied in a state of being included in a suspension. A method ofsupplying the micro display elements 520 included in the suspension mayinclude various methods such as a spray method, a dispensing method fordropping a liquid, an inkjet dot method for discharging a liquid like aprinting method, and a method for flowing the suspension onto thetransfer substrate 510. In addition, the transfer substrate 510 may bescanned by an absorbent member 540 capable of absorbing a liquid. Theabsorbent member 540 may be any material as long as the material iscapable of absorbing a liquid, and its shape or structure is notlimited. The absorbent member 540 may include, for example, fabric,tissue, polyester fiber, paper, or a wiper. The absorbent member 540 maybe used alone without other auxiliary tools and may be coupled to asupport 550 for convenient scanning of the transfer substrate 510without being limited thereto. The support 550 may have various shapesand structures suitable for scanning the transfer substrate 510. Thesupport 550 may have a shape of, for example, a rod, a blade, a plate,or a wiper. The absorbent member 540 may be provided on one side of thesupport 550 or may surround the support 550.

The absorbent member 540 may scan the transfer substrate 510 whilepressing the transfer substrate 510 with an appropriate pressure.Scanning may include a step in which the absorbent member 540 passesover the plurality of grooves 505 to absorb a liquid while being incontact with the transfer substrate 510. The scanning may be performedin various methods such as a sliding method, a rotating method, atranslating method, a reciprocating method, a rolling method, a spinningmethod, and/or a rubbing method of the absorbent member 540 and mayinclude both a regular method and an irregular method. The scanning mayalso be performed by moving the transfer substrate 510 instead of movingthe absorbent member 540, and scanning of the transfer substrate 510 maybe performed by the sliding method, the rotating method, the translatingmethod, the reciprocating method, the rolling method, the spinningmethod, and/or the rubbing method. The scanning may also be performed bycooperation of the absorbent member 540 and the transfer substrate 510.In this way, the micro display elements 520 may be transferred onto thetransfer substrate 510 by using a fluidic self-assembly method.According to a display manufacturing method of an example embodiment,each of the drive electrodes 450 shown, e.g., in FIG. 16 has one of thestructures illustrated in FIGS. 3 to 8 , and thus, the micro displayelements 520 may be connected to electrode pads of wiring lines nomatter in which direction the micro display elements 520 aretransferred.

An example method of manufacturing a display apparatus may include amethod of forming metal lines in micro display elements to electricallyconnect the transferred micro display elements to each other, or amethod of bonding and transferring micro display elements to a transfersubstrate on which metal lines are formed. As described above, a microlight emitting element including both of a drive unit and a micro lightemitting unit monolithically coupled to each other is transferred onto atransfer substrate, and thus, a structure, a material, a process, and soon of the transfer substrate may be freely selected without variousrestrictions in a case where the drive unit including a TFT and so on isformed on the transfer substrate. For example, the transfer substrate510 may include various materials such as glass, silicon, and polymer.

A backplane substrate including TFTs, capacitors, and so on isdiversified in usage and material to be applied to various elements.However, when the backplane substrate is manufactured by using the LTPSprocess, the backplane substrate is difficult to be manufactured in alarge area. Because vacuum deposition equipment is costly, it costs alot to form TFTs on a large-area backplane substrate, and it isdifficult to ensure uniformity of the large-area backplane substrate. Inaddition, a high-temperature process may be difficult to be performeddepending on TFT materials, and thus, an alternative element such as anoxide TFT may be used for a large-area substrate.

As such, according to an example embodiment, a drive unit in a fluidself-assembly method, a display in which a high-performance drive unitis monolithically integrated into a micro light emitting unit may bemanufactured by transferring a micro display element including a microlight emitting unit and a drive unit in a fluidic self-assembly method.In this case, a display may be manufactured regardless of an area and atype of a substrate thereof, and thus, displays of various form factorsmay be manufactured.

FIG. 18 is a block diagram of an electronic apparatus including adisplay apparatus according to an example embodiment.

Referring to FIG. 18 , an electronic apparatus 8201 may be provided in anetwork environment 8200. In the network environment 8200, theelectronic apparatus 8201 may communicate with another electronicapparatus 8202 through a first network 8298 (a short-range wirelesscommunication network or so on) or may communicate with anotherelectronic apparatus 8204 and/or a server 8208 through a second network8299 (a long-distance wireless communication network or so on). Theelectronic apparatus 8201 may communicate with the electronic apparatus8204 through the server 8208. The electronic apparatus 8201 may includea processor 8220, a memory 8230, an input device 8250, a sound outputdevice 8255, a display apparatus 8260, an audio module 8270, a sensormodule 8276, an interface 8277, a haptic module 8279, a camera module8280, a power management module 8288, a battery 8289, a communicationmodule 8290, a subscriber identification module 8296, and/or an antennamodule 8297. Some of the components may be omitted from the electronicapparatus 8201, or other components may be added to the electronicapparatus 8201. Some of the components may be integrated in one circuit.For example, the sensor module 8276 (a fingerprint sensor, an irissensor, an illuminance sensor, or so on) may be embedded in the displayapparatus 8260 (a display or so on).

The processor 8220 may execute software (such as a program 8240) tocontrol one or a plurality of other components (hardware, softwarecomponents, and so on) of the electronic apparatus 8201 connected to theprocessor 8220 and may perform various data processing or arithmetic.The processor 8220 stores commands and/or data received from othercomponents (the sensor module 8276, the communication module 8290, andso on) in a volatile memory 8232 and process the commands and/or thedata stored in the volatile memory 8232 and store resulting data in anon-volatile memory 8234 as part of data processing or arithmetic. Theprocessor 8220 may include a main processor 8221 (a central processingunit, an application processor, or so on) and a co-processor 8223 (agraphics processing unit, an image signal processor, a sensor hubprocessor, a communication processor, or so on) that may be operatedindependently or together therewith. The co-processor 8223 may use lesspower than the main processor 8221 and may perform a specializedfunction.

The co-processor 8223 may control functions and/or states related tosome components (the display apparatus 8260, the sensor module 8276, thecommunication module 8290, and so on) of the electronic apparatus 8201on behalf of the main processor 8221 while the main processor 8221 is inan inactive state (sleep state), or together with the main processor8221 while the main processor 8221 is in an active state (theapplication execution state). The co-processor 8223 (an image signalprocessor, a communication processor, or so on) may be implemented aspart of another component (the camera module 8280, the communicationmodule 8290, or so on) functionally related thereto.

The memory 8230 may store various data required by components (theprocessor 8220, the sensor module 8276, and so on) of the electronicapparatus 8201. Data may include, for example, input data and/or outputdata for software (such as the program 8240) and commands relatedthereto. The memory 8230 may include the volatile memory 8232 and/or thenon-volatile memory 8234.

The program 8240 may be stored as software in the memory 8230 and mayinclude an operating system 8242, middleware 8244, and/or an application8246.

The input device 8250 may receive commands and/or data to be used incomponents (the processor 8220 and so on) of the electronic apparatus8201 from an exterior (a user or so on) of the electronic apparatus8201. The input device 8250 may include a remote controller, amicrophone, a mouse, a keyboard, and/or a digital pen (a stylus pen orso on).

The sound output device 8255 may output a sound signal to the exteriorof the electronic apparatus 8201. The sound output device 8255 mayinclude a speaker and/or a receiver. The speaker may be used for generalpurposes such as multimedia playback or recording playback, and thereceiver may be used to receive incoming calls. The receiver may beintegrated in the speaker as part of the speaker or may be implementedas an independent separate device.

The display apparatus 8260 may visually provide information to theexterior of the electronic apparatus 8201. The display apparatus 8260may include a control circuit for controlling a display, a hologramapparatus, or a projector and a corresponding device. The displayapparatus 8260 may include the display apparatus described withreference to FIGS. 1 to 13 and may be manufactured by the manufacturingmethod described with reference to FIGS. 14 to 17 . The displayapparatus 8260 may include touch circuitry configured to sense a touch,and/or sensor circuitry configured to measure the intensity of forcegenerated by the touch (a pressure sensor or so on).

The audio module 8270 may convert audio into an electrical signal or mayconvert an electrical signal into audio. The audio module 8270 mayacquire audio through the input device 8250 or may output audio througha speaker and/or a headphone of the sound output device 8255, and/oranother electronic apparatus (the electronic apparatus 8202) directly orwirelessly connected to the electronic apparatus 8201.

The sensor module 8276 may detect an operation state (power,temperature, and so on) of the electronic apparatus 8201 or an externalenvironmental state (user state or so on) and may generate an electricalsignal and/or a data value corresponding to the detected state. Thesensor module 8276 may include a gesture sensor, a gyro sensor, anatmospheric pressure sensor, a magnetic sensor, an acceleration sensor,a grip sensor, a proximity sensor, a color sensor, an infrared (IR)sensor, a biometric sensor, a temperature sensor, a humidity sensor,and/or an illuminance sensor.

The interface 8277 may support one or more designated protocols that maybe used for the electronic apparatus 8201 to be connected directly orwirelessly to another electronic apparatus (the electronic apparatus8202 or so on). The interface 8277 may include a high-definitionmultimedia interface (HDMI), a Universal Serial Bus (USB) interface, asecure digital (SD) card interface, and/or an audio interface.

A connection terminal 8278 may include a connector through which theelectronic apparatus 8201 may be physically connected to anotherelectronic apparatus (for example, the electronic apparatus 8202). Theconnection terminal 8278 may include an HDMI connector, a USB connector,an SD card connector, and/or an audio connector (a headphone connectoror so on).

The haptic module 8279 may convert an electrical signal into amechanical stimulus (vibration, movement, or so on) or an electricalstimulus that a user may perceive through a tactile or motor sense. Thehaptic module 8279 may include a motor, a piezoelectric element, and/oran electrical stimulation element.

The camera module 8280 may capture a still image and a video. The cameramodule 8280 may include a lens assembly including one or more lenses,image sensors, image signal processors, and/or flashes. The lensassembly included in the camera module 8280 may collect light emittedfrom a subject to be imaged.

The power management module 8288 may manage power supplied to theelectronic apparatus 8201. The power management module 8288 may beimplemented as part of a power management integrated circuit (PMIC).

The battery 8289 may supply power to configuration elements of theelectronic apparatus 8201. The battery 8289 may include anon-rechargeable primary cell, a rechargeable secondary cell, and/or afuel cell.

The communication module 8290 may establish a direct (wired)communication channel and/or a wireless communication channel betweenthe electronic apparatus 8201 and another electronic apparatus (theelectronic apparatus 8202, the electronic apparatus 8204, the server8208, or so on), and may support communication through the establishedcommunication channel. The communication module 8290 may operateindependently of the processor 8220 (application processor or so on) andmay include one or more communication processors that support directcommunication and/or wireless communication. The communication module8290 may include a wireless communication module 8292 (a cellularcommunication module, a short-range wireless communication module, aglobal navigation satellite system (GNSS) communication module, or soon) and/or a wired communication module 8294 (a Local Area Network (LAN)communication module, a power line communication module, or so on). Acorresponding communication module among these communication modules maycommunicate with another electronic apparatus through the first network8298 (a short-range communication network such as Bluetooth, WiFiDirect, or infrared data association (IrDA)) or the second network 8299(a telecommunication network such as a cellular network, the Internet,or a computer network (a LAN, a wide area network (WAN), or so on)).Various types of these communication modules may be integrated into oneconfiguration element (a single chip or so on) or may be implemented asa plurality of separate configuration elements (multiple chips). Thewireless communication module 8292 may check and authenticate theelectronic apparatus 8201 in a communication network such as the firstnetwork 8298 and/or the second network 8299 by using subscriberinformation (international mobile subscriber identifier (IMSI) and soon) stored in the subscriber identification module 8296.

The antenna module 8297 may transmit a signal and/or power to theoutside (other electronic apparatuses or so on) or may receive a signalfrom the outside. An antenna may include a radiator made of a conductivepattern formed on a substrate (a printed circuit board (PCB) or so on).The antenna module 8297 may include one or a plurality of antennas. Whena plurality of antennas are included, an antenna suitable for acommunication method used in a communication network such as the firstnetwork 8298 and/or the second network 8299 may be selected from amongthe plurality of antennas by the communication module 8290. A signaland/or power may be transmitted or received between the communicationmodule 8290 and other electronic apparatuses through the selectedantenna. In addition to the antenna, other components (a radio frequencyintegrated circuit (RFIC) and so on) may be included as some of theantenna module 8297.

Some of the configuration elements may be connected to each otherthrough a communication method (bus, general purpose input and output(GPIO), serial peripheral interface (SPI), mobile industry processorinterface (MIPI), or so on) between peripheral devices and mayinterchange signals (commands, data, and so on).

A command or data may be transmitted or received between the electronicapparatus 8201 and the electronic apparatus 8204, which is external,through the server 8208 connected to the second network 8299. The otherelectronic apparatuses 8202 and 8204 may be the same apparatuses as ordifferent types of apparatuses from the electronic apparatus 8201. Allor some of operations performed by the electronic apparatus 8201 may beperformed by one or more of the other electronic apparatuses 8202, 8204,and 8208. For example, when the electronic apparatus 8201 needs toperform a function or service, the electronic apparatus may request oneor more other electronic apparatuses to perform the function or part orall of the service, instead of performing the function or service byitself. One or more other electronic apparatuses that receive a requestmay perform an additional function or service related to the request andmay transmit a performance result to the electronic apparatus 8201. Tothis end, a cloud computing technology, a distributed computingtechnology, and/or a client-server computing technology may be used.

FIG. 19 illustrates an example in which the electronic apparatusaccording to an example embodiment is applied to a mobile apparatus. Themobile apparatus 9100 may include a display apparatus 9110, and thedisplay apparatus 9110 may include the display apparatuses describedwith reference to FIGS. 1 to 13 . The display apparatus 9110 may have afoldable structure, for example, a multi-foldable structure.

FIG. 20 illustrates an example in which the display apparatus accordingto an example embodiment is applied to a vehicle. The display apparatusmay include a head-up display apparatus 9200 for a vehicle and mayinclude a display 9210 provided in one region of the vehicle and a lightpath modification member 9220 that converts a light path such that adriver may see an image generated by the display 9210.

FIG. 21 illustrates an example in which the display apparatus accordingto an example embodiment is applied to augmented reality glasses orvirtual reality glasses. An augmented reality glasses 9300 may include aprojection system 9310 that forms an image, and an element 9320 thatguides the image from the projection system 9310 into a user's eye. Theprojection system 9310 may include the display apparatuses describedwith reference to FIGS. 1 to 13 .

FIG. 22 illustrates an example in which the display apparatus accordingto an example embodiment is applied to a large-sized signage. A signage9400 may be used for outdoor advertisement using a digital informationdisplay and may control advertisement contents and so on through acommunication network. The signage 9400 may be implemented through, forexample, the electronic apparatus described with reference to FIG. 18 .

FIG. 23 illustrates an example in which the display apparatus accordingto an example embodiment is applied to a wearable display. A wearabledisplay 9500 may include the display apparatuses described withreference to FIGS. 1 to 13 and may be implemented by the electronicapparatuses described with reference to FIG. 18 .

A display apparatus according to the example embodiments may be appliedto various products such as a rollable TV and a stretchable display.

A display apparatus according to the example embodiments may include amicro light emitting element in which a drive unit including driveelectrodes is integrally provided in a micro light emitting unit, andthus, a high-performance and large-area display apparatus may beprovided without limitation of a substrate for manufacturing the driveunit.

It should be understood that embodiments described herein should beconsidered in a descriptive sense only and not for purposes oflimitation. Descriptions of features or aspects within each embodimentshould typically be considered as available for other similar featuresor aspects in other embodiments. While one or more embodiments have beendescribed with reference to the figures, it will be understood by thoseof ordinary skill in the art that various changes in form and detailsmay be made therein without departing from the spirit and scope asdefined by the following claims.

What is claimed is:
 1. A micro display element comprising: a microlight-emitting unit configured to emit light; and a drive unitcomprising a drive transistor and a drive electrode configured to drivethe micro light-emitting unit, wherein the micro light-emitting unit ismonolithically coupled to the drive unit.
 2. The micro display elementof claim 1, further comprising an insulating layer between the microlight-emitting unit and the drive unit.
 3. The micro display element ofclaim 1, further comprising a reflective layer between the microlight-emitting unit and the drive unit.
 4. The micro display element ofclaim 1, wherein the drive unit further comprises a plurality of driveelectrodes provided at different distances from a center of the driveunit.
 5. The micro display element of claim 1, wherein the drive unitcomprises at least two transistors and at least one capacitor.
 6. Themicro display element of claim 1, having a horizontal electrodestructure in which an electrode is disposed in one direction.
 7. Themicro display element of claim 1, configured to emit blue light.
 8. Adisplay apparatus comprising: a display substrate; a plurality ofdisplay elements, each of the plurality of display elements comprising amicro light-emitting unit and a drive unit, the drive unit comprising adrive transistor and a drive electrode to drive the micro light-emittingunit, wherein the micro light-emitting unit and the drive unit aremonolithically coupled to each other, and the plurality of displayelements are spaced apart from each other in units of sub-pixels on thedisplay substrate; and a color conversion layer formed over the displayelement for each sub-pixel.
 9. The display apparatus of claim 8, furthercomprising an insulating layer between the micro light-emitting unit andthe drive unit.
 10. The display apparatus of claim 8, further comprisinga reflective layer between the micro light-emitting unit and the driveunit.
 11. The display apparatus of claim 8, wherein the drive unitfurther comprises a plurality of drive electrodes provided at differentdistances from a center of the drive unit.
 12. The display apparatus ofclaim 8, wherein the drive unit comprises at least two transistors andat least one capacitor.
 13. The display apparatus of claim 8, whereinthe display element has a horizontal electrode structure in which anelectrode is disposed in one direction.
 14. The display apparatus ofclaim 8, wherein the color conversion layer comprises quantum dots. 15.The display apparatus of claim 8, wherein the display element emits bluelight.
 16. The display apparatus of claim 15, wherein, when the displayelement emits blue light, the color conversion layer comprises only ared conversion layer and a green conversion layer.
 17. A method ofmanufacturing a display apparatus, the method comprising: forming amicro light-emitting unit on growth substrate; forming a drive unitmonolithically on the micro light-emitting unit, wherein the drive unitcomprising a drive transistor and a drive electrode to drive the microlight-emitting unit; etching the micro light-emitting unit and the driveunit to integrally form display elements; removing the growth substrateto separate the display elements; a first transfer operation oftransferring the separated display elements to a transfer substrate inunits of sub-pixels of the display apparatus; a second transferoperation of transferring the display elements on the transfer substrateto a display substrate on which wiring corresponding to the drive unitis formed; and forming a color conversion layer over the displayelements to correspond to each of the display elements.
 18. The methodof claim 17, wherein the display substrate is one of a rigid substrateand a flexible substrate.
 19. The method of claim 17, wherein, in thefirst transfer operation, the display elements are transferred by afluid self-assembly method.
 20. The method of claim 17, wherein thecolor conversion layer comprises quantum dots.
 21. A method ofmanufacturing a display apparatus, the method comprising: forming amicro light-emitting unit on a growth substrate; forming a drive unitmonolithically over the micro light-emitting unit, the drive unitcomprising a drive transistor and a drive electrode to drive the microlight-emitting unit; etching the micro light-emitting unit and the driveunit to integrally form display elements; removing the growth substrateto separate the display elements; transferring the separated displayelements to a display substrate in units of sub-pixels of the displayapparatus; forming wiring corresponding to the drive unit over thedisplay elements; and forming a color conversion layer over the driveunit.
 22. The method of claim 21, wherein the display substrate is oneof a rigid substrate and a flexible substrate.
 23. The method of claim21, wherein, in the transferring of the separated display elements, thedisplay elements are transferred by a fluid self-assembly method. 24.The method of claim 21, wherein the color conversion layer comprisesquantum dots.